This Canadian population-based study observed an increase in the short-term risk for hospital admission with acute kidney injury in older patients starting treatment with a PPI compared to matched controls not prescribed PPIs. The authors say that their findings are in agreement with those from three previous case-control studies.
The study reports that over half (59%) of patients on PPI therapy admitted with acute kidney injury received a further prescription for a PPI following discharge; of these 42 (7.5%) were readmitted to hospital with acute kidney injury in the ensuing 120 days. Given this low risk of recurrence following rechallenge, the authors suggest however that the association between PPIs and acute kidney injury may be overstated.
They go on to acknowledge the limitations of their study, including the reliance on administrative data, lack of data on renal function, renal biopsy results, treatment indication or medication adherence, and lack of information on use of any non-prescription medicines (e.g. NSAIDs) that may have influenced the risk of acute renal outcomes. As with all observational studies, it is possible that unmeasured confounders or intergroup differences in baseline risk may have affected the results.
The authors caution clinicians to maintain a high index of suspicion for acute interstitial nephritis among patients taking PPIs who present with a decline in renal function, particularly at the outset of treatment. They also recommend against the indiscriminate use of PPIs; those taking these medicines should be monitored appropriately.